Resumen

GUERRERO, D. R; KRYVENKI, M  y  DOMINGUEZ, M. Evaluación morfológica y fenológica de 10 clones de yerba dulce (Stevia rebaudiana) según el tiempo térmico. RIA. Rev. investig. agropecu. [online]. 2015, vol.41, n.3, pp.317-324. ISSN 1669-2314.

Sweet herb crop is consolidating as a productive alternative for Misiones province. The aim of this work was to compare ten clones of Stevia (treatments) with respect to morphological variables and thermal time accumulation in the different phenological stages and phases. Observation period was September 2010 to April 2011. Residual method was used to calculate degree-days, taking 10 °C as base temperature. Morphological variables showed significant differences between treatments for number of expanded leaves, number of secondary stems, number of internodes and plant height in cm, and not for number of primary stems. Clone T9-STK12 required the greatest thermal time accumulation to complete vegetative stage (1993 degree days). To inicciate reproductive stage (flower bud) clones needed to accumulate between 1596 (T9-STK12) and 857 (T1-STE21) degree-days. Overlapping stages were observed in all treatments. Reproductive stage was divided into three stages (flower bud, open flower and fruit) and required to be complete between 1664 (T1-STE21) and 925 (T9- STK12) degree-days. This work allowed us to quantify morphological variables previous unknown for these clones and to evaluate their phenological behaviour. These results could be useful to establish appropriate crop management (leaves or seeds harvesting) and selection of new genetic material from controlled crossing.

Palabras clave : Degree-days; Phase; Stage; Residual method.